Research

My main research focuses on how populations of birds vary in morphology, genetics, song, and/or ecology, especially in western North America. These data are used to study species limits, re-assess taxonomy, and examine contact zones between divergent lineages.

I have also been involved in the Grinnell Resurvey Project, which aims to resurvey historical sites in California to study changes in vertebrate communities, species distributions, and phenotypic/genotypic traits over the past century. Specimen-based resurveys have focused on the Mt. Lassen region, southern Sierra Nevada region, and western deserts.

Most of my field work has been concentrated in the western United States, including Alaska, Arizona, California, Colorado, Idaho, Montana, Nevada, New Mexico, Oregon, Utah, Washington, Wyoming. I also have done field work in Canada (British Columbia, Newfoundland, Ontario, Quebec), Guatemala, Paraguay, and the Dominican Republic.